Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose-6- phosphate to fructose-1,6-bisphosphate, an early step of glycolysis. In the presence of oxygen, an increase in the amount ATP in a cell would be expected to

A) inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle.

B) activate the enzyme and thus slow the rates of glycolysis and the citric acid cycle.

C) inhibit the enzyme and thus increase the rates of glycolysis and the citric acid cycle.

D) activate the enzyme and increase the rates of glycolysis and the citric acid cycle.

E) inhibit the enzyme and thus increase the rate of glycolysis and the concentration of citrate.

A) inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle.

In vertebrate animals, brown fat tissue's color is due to abundant mitochondria. White fat tissue, on the other hand, is specialized forfat storage and contains relatively few mitochondria. Brown fat cells have a specialized protein that dissipates the proton-motive force across the mitochondrial membranes. Which of the following might be the function of the brown fat tissue?

A) to increase the rate of oxidative phosphorylation from its few mitochondria

B) to allow the animals to regulate their metabolic rate when it is especially hot

C) to increase the production of ATP synthase

D) to allow other membranes of the cell to perform mitochondrial function

E) to regulate temperature by converting energy from NADH oxidation to heat

E) to regulate temperature by converting energy from NADH oxidation to heat